Since entering the 21st century, humanity has progressed into the information automation age, and as an important part in a display element, Thin Film Transistor (TFT) is rapidly developed in visual fields such as a mobile phone and a television.
At present, in an industry of Thin Film Transistor-Liquid Crystal Display (TFT-LCD) and Active Matrix-Organic Light Emitting Diode (AM-OLED), a raw material for making a panel is a glass substrate with a thickness of about 0.3-0.7 mm, and its area may reach 2000×2500 mm2. Such a large, thin and crisp glass substrate is very easy to damage in actual production. Once the glass substrate is damaged, glass fragments will greatly affect a production device which has high requirements in both automation and cleanliness. Meanwhile, the glass substrate needs to be treated for a relatively long time after damage, especially for some important devices, for example a coating machine and an exposure machine. Therefore, screening glass substrate damage on an automatic production line is particularly important.
Substrate damage inspection technologies known in the prior art mostly support inspection for an edge of the substrate, which mainly include the three types as follows.
The first one is of image analysis type. That is, in a flowing process of substrate, continuously photographing the substrate, and then analyzing the image, thereby determining whether an edge of the substrate has a defect. A disadvantage of this solution is that an inspection range is limited, only the edge may be inspected, and the substrate can not be completely inspected. Moreover, when the substrate is insufficiently clean, false perception is easily caused in this solution, thereby leading to an incorrect inspection result.
The second one is of optical fiber sensor detection type. That is, respectively installing a reflection type optical fiber sensor at two sides of a device. When the substrate flows through, based on the amount of light received by a receiving end, detect substrate damage on straight lines at two sides. A disadvantage of this solution is that there is a relatively high limitation to an installing position, which makes it difficult to detect a condition of the substrate when transmitting on a manipulator; the detection belongs to a linear type, resulting in a limited detection range; meanwhile, false perception is easily caused when the substrate actually cooperates with a control unit, thus leading to a low reliability.
The third one is of a full-scale type. That is, substrate damage is inspected with regional type detection. However, full-scale inspection is only performed on the substrate damage when the substrate flows horizontally. A disadvantage of this solution is that it is only suitable for inspection when the substrate moves in a horizontal direction. For a case where the substrate moves in a vertical direction, a defect of the substrate can not be detected.
In an implementation of the above prior art, the first two types have been applied in actual production and used in a device before a primary process, but the third type has not been applied yet. However, due to many problems in the above prior art, the substrate damage can not be inspected when the substrate moves vertically. That is, the glass substrate damage can not be detected in a vertical direction.
Therefore, to address the above deficiencies, there is a need for a substrate damage inspection apparatus capable of realizing a substrate damage inspection in a vertical direction, a production system and an inspection method.